Pneumatic action for self-playing pianos.



W. A. KRUGK.

PNEUMATIC ACTION FOB SELF PLAYING PIANOS.

APPLICATION FILED APR. 27, 1911.

Patented May 21, 1912.

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0Q K H wue wto'c 1 This invention consists of certain cylinder andpiston devices, usually. of metal, and,

To it'may wnnzrnnaa xnuc'xgor ca'mbnu, NEW JERSEY.

frnmmarrc nor-Ion r012. SELF-PLAYING- PIANOS.

Be it known that I, WALTER; A. Knock, citizen of'the UnitedStates,-.residing at Camden, in the, county of Camden and State of NewJersey,'have invented certain new and useful Improvements in PneumaticAc.

tions for Self-Playing Pianos, of .which'the O WiII is a specification.a

This invention relates Ito pneumaticjactions for self-playing pianos,and the like,

- and belongs withthat class of cont-rivances interposed between. thesuction chamber common to all players actuated ,by atmoscylindricalvalve operating pheric pre.

sure, and the mechanical piano a'c-tionfor striking the strings.

having special construction and special arrangement with respect to eachother, whereby it is believed one or more of the customary bellowsneumatics-are done away with for each-pianokey, and, the

whole apparatus thus rendered..i'elatively much more durable andlasting.

The Special Parts pr g this inyefi ti'on and their lent with respect toeach other, are set out in theaccompanying drawings, of which trated insection, to disclose internal ele'- ments; Fig. 2 is an exterior view ofthe lower portion of the valve-operating cyl1n-- der, showing therelative positions ofi the" larger and smaller tubularprojectinpartsvthereof. Fig. 3 is a top plan view,.s owing; the interior of the lowerportion of the valve-operatincylinder.

In all the views and in the following description, the Same letter ofreference is used to designate the same..part..

' Considering Fig. "1', the suction-chamber is referred to by theletter'A, and a partlal;

vacuum 'is created and maintained therein by a suitable exhaustingbellows B, con- "nected with the suction chamber, and operated by atreadle C. Secured upon the suction chamber, is the-lower portion D ofthe devices. The lower portion D has two, inclined projecting tubularparts, of which the larger tube E slants downwardly, and, the smallertube F extends upwardly. A suitable connection G puts the large tubularprojection E in communication with the suction chamber A. Another pipeH, connects the smaller pro- Specification tit-Letters mes.hpplteatioaflled nn-i127, i911. Seria11i'o.623,614.

Figure l "represents-a sideiviewof all the; parts assembled, some ofwhich are 1'lll1S+;

'fect'ive v o li'tssing t rough the bottom of the piston S 'is a smallair ducts, to be again referred to. l r From the piston S, the valve.rod T extends upwardly through the nipple U, that jecting tubularportion F mentioned, with the tracker J. The upper portion K of thecylindrical valve operating devices, is best lllustrated'also in Fig. 1.It has an opening L in its top, bular'projecting part M. p v

The two cylindrical portions D and K are cup-shapeda-s shown in Fig. 1,the sides and bottom of each being in one piece. The portion D isinverted and its bottom is uppermost as the partsare assembled.-

It will be noted that the lower portion D PatentedMay21,1912.

and a downwardly-inclined tu of the cylindrical valve-operating devices,

and the upper portion K thereof, are provided at their months withinternal threads i N and 0, 5nd that those threads hermit the 1 1. upperportion K and thelower portion D to be ad ustably joined by the couplingP,

threaded externally as "shown. And, the relative positions ofthe-coupling andthe portions of the cylinder connected by it,

Q, and R, actingv as jam nuts against the port'ionsD and K asillustrated in Fig. 1.

Within the lower portion D of the cylinmay be fixed by means of the tworing nuts drical valve-operating devices is located a piston S, usually,cup-shaped and made of the same metal as. theportion D, in order-toavoid binding due'to changes of temper- ;ature. The cylindricalP01111011 -'D is bored carefully interiorly,* and" the piston S isturned with equal care to fit it-fniovably,

without. packing, and as'closely asv the efrat-ion'of-the parts willadmit.

is formed integrally with the coupling P, and the mouth of which,designated by the letter V, is formed as a valve seat for the .valve 2.By constructing thepiston'. S cupsha'ped as illustrated anddescribed, itdoes.

not wabble in the cylinder but movesdiing the valve rod T withoutspecial guiding '100 rectly up and :down, thus adequately vguidmeanstherefor. It will be noted that the valve rod T is'threaded at its'upperend, and that the valve t is, therefore, adjustable on the rod. The nutemployed to fix the position of the valve on the rod is marked W. Aspreviously explained, and as illustrated in Fig. 1, the upper portion Kof the cylindrical valve-operating devices, is provided with the tubularprojecting part M, and, it will be seen, that the tube M is joined by-apipe X to the air duct Y in a block Z, upon which is secured theactionoperating cylinder 1. The cylinder 1 is in communlcat-ion withtheduct as shown. Within the cylinder lis a cupped piston 2, made, usually,of the same material as the cylinder, to avoid binding due to changes oftemperature. The cylinder 1 1s. bored out carefully, and the piston 2 isturned with equal care to fit the cylinder movably without packing, andas closely asthe efiective operation will admit. Piston 2 ordinarily hasa guide rod 3 projecting centrally below it, and passing through a smallhole 4 in the bottom of the cylinder. It is likewise customary to placea disk of felt next to the bot-tom of the piston 2, shown in Fig. 1 andmarked 5, to cushion the blow' of the descending piston upon the bottomof the cylinder 1. On its upper side, the piston 2 is pivotallyconnected by the link 6, with the lever 7, of the mechanical pianoaction.

The operation of this invention may be explained by stating that thepartial vacuum in the suction chamber being created and maintained, theair is exhausted directly from within the lower portion D of thecylindrical valve-operating devices through the larger tubular proection E,

which communicates with the portion D above the piston S. By way of theduct 8 the air is taken from below the piston S, and by way of thesmaller tubular projection F, the air is exhausted from the pipe I-Iconnected with the tracker J.

It has been explained that the top of the upper portion K of thecylindrical valveoperating devices has an opening to the atmosphere,and, therefore, the suctlon keeps valve t seated upon the seat V of thenipple U. So long as the tracker is covered by the sheet in the usualmanner, the partial vacuum will be maintained. An orifice 8 of thetracker being uncovered, air enters beneath piston S, raising thepiston, and, consequently, valve t, which, being a doubleface valve asshown, closes the opening L in the upper cylindrical portion K throughthe top thereof, and allows the air to be exhausted from 'beneath thepiston 2 in the action-operating cylinder 1, and operates the lever 7,of the piano action. It may be that the orifice 8 of the tracker isquickly opened and immediately closed, admitting but relatively littleair beneath piston S. But, the piston S has considerably greatersuperficial area't-h'an valve t, and, therefore,

the pressure although it may be lower, raises the smaller valve againstthe pressure of the external air. The tracker orifice 8 being closed,the air admitted beneath the piston S is, very rapidly, taken away intothe suction chamber, and the operation may be quickly repeated. In otherwords, the

.same note may be sounded as often as dewhat I'claim and desire tosecure by Let- .ters-Patent of the United States, is

1. In a pneumatic action, the combination with upper and lowercup-shaped portions, said upper portion being inverted and having anopening in its bottom, of a coupling constructed to engage both of saidportions adjustably, the said coupling having a nipple extending intosaid inverted portion and provided with a valve seat, pneumatickey-operating devices, tubular connections leading from said devices andopening into said inverted portion above said valve seat, a valvearranged to cover alternately said seat and the said opening in saidinverted portion, a cup-shaped piston movably fittin said lower portion,a valve rod bearing said valve at one end, said rod being rigidlyattached to and guided by said iston, a tracker, tubular connectionsleading from the tracker and opening into said lower portion below saidpiston, a suction chaimber, and tubular connections leading from thesuction chamber and opening into said lower portion above said. piston.

2. In a pneumatic action, the combination with upper and lowercup-shaped portions, said upper portion being inverted and having anopening in its bottom, of a coupling constructed to adjustably engageboth. of said portions, the said coupling having a nipple extending intosaid inverted portion and provided with a valve seat, pneumatickey-operating devices, tubular I connections leading from said devicesand opening into said inverted portion above the valve seat,

a valve arranged to cover alternately said seat and said opening in saidinverted portion, a cup'shaped piston provided with an air duct andmovably fitting said lower portion, a valve rod bearing said valve atone end, said rod being rigidly attached to and guided by said piston, atracker, tubular connection. leading from the tracker and opening intosaid lower portion below said, piston, a suction chamber, and tubularconnections leading from the suction chamber and opening into said lowerportion above the said piston.

In testimony whereof I affix my signature in presence of two Witnesses.

WALTER A. KRUOK;

Witnesses:

-WILLIAM P. WALSH,

EDWA D RICHARDSON.

